How can i fix Laravel Autoload Error in Index.php?

[Mon Jul 20 09:54:57.082115 2020] [proxy_fcgi:error] [pid 9434:tid 140041913337600] [client 95.70.132.39:43011] AH01071: Got error 'PHP message: PHP Warning:  require(/var/www/vhosts/mydomain/httpdocs/vendor/autoload.php): failed to open stream: No such file or directory in /var/www/vhosts/mydomain/httpdocs/index.php on line 24PHP message: PHP Fatal error:  require(): Failed opening required '/var/www/vhosts/mydomain/httpdocs/vendor/autoload.php' (include_path='.:/opt/plesk/php/7.4/share/pear') in /var/www/vhosts/mydomain/httpdocs/index.php on line 24'

I got this error when i changed my hosting company.

I tried composer install and composer update.

    <?php

/**
 * Laravel - A PHP Framework For Web Artisans
 *
 * @package  Laravel
 * @author   Taylor Otwell <taylor@laravel.com>
 */

define('LARAVEL_START', microtime(true));

require __DIR__.'/vendor/autoload.php';

$app = require_once __DIR__.'/bootstrap/app.php';

$kernel = $app->make(Illuminate\Contracts\Http\Kernel::class);

$response = $kernel->handle(
    $request = Illuminate\Http\Request::capture()
);

$response->send();

$kernel->terminate($request, $response);

Also this is my index.php file.

via Chebli Mohamed